A plasma display panel (hereinafter, referred to as “PDP”) is a gas discharge display device having the following construction. In a PDP, a front panel in which a plurality of display electrode pairs are set, and a back panel in which a plurality of data electrode pairs which are writing electrodes are set, are arranged. The front panel and the back panel are arranged so that the display electrode pairs cross over the data electrode pairs. Discharge cells are arranged in a matrix by enclosing a discharge gas dischargeable in a discharge space in a display area so that a discharge space is provided between both substrates of the front panel and the back panel.
FIG. 6 is a schematic perspective view showing a construction of a discharge cell in a display area of an AC-type PDP according to a conventional technology. FIG. 6 is partially broken to show an internal construction, in which four discharge cells are arranged in parallel with each other.
In the PDP shown in FIG. 6, a front panel 2 and a back panel 3 are arranged in opposition to each other. A display electrode pair 4 composed of a scan electrode 5 and a sustain electrode 6 is arranged on a glass substrate 10 of the front panel 2. Also, a dielectric layer 7 and a protection film 8 which is composed of MgO (magnesium oxide) and the like are formed so as to cover the display electrode pair 4. On the other hand, a data electrode 12 for writing display information is formed on a substrate 11 of the back panel 3, and a dielectric layer 13 is formed so as to cover the data electrode 12. A barrier rib 14 is formed on the dielectric layer 13 so as to be located between adjacent discharge cells in parallel with the data electrode 12. A phosphor layer 15 for RGB is formed on a surface of the dielectric layer 13 and a side of the barrier rib 14 for each discharge cell.
The data electrode 12 and the barrier rib 14 are arranged so as to cross over the display electrode pair 4. A discharge cell which is a pixel unit is formed in an area in which the data electrode 12 crosses over the display electrode pair 4. A mixed gas of Ne (neon) and Xe (xenon) and the like as a discharge gas is filled in a discharge space 1 at a pressure of several tens of kPa.
When driving a PDP, an image is displayed by the following operation. In a display period after a data writing period, an AC voltage is applied between the scan electrode 5 and the sustain electrode 6 composing the display electrode pair 4 with a discharge gap G therebetween to selectively generate a discharge in a discharge cell. The phosphor layer 15 is excited by an ultraviolet ray radiated from a Xe atom and a Xe molecule which are excited by the discharge, thereby generating visible light.
As shown in FIG. 6, in a plan view, the scan electrode 5 and the sustain electrode 6 are extended in a direction perpendicular to the barrier rib 14 in a stripe state, and each of the scan electrode 5 and the sustain electrode 6 is composed of a transparent electrode 55 and a bus electrode 59 for electric power supply.
The transparent electrode 55 has a high light transmittance, and is formed on the glass substrate 10 in a substantially large width in parallel with the other transparent electrode 55, with the discharge gap G therebetween. A projection which projects toward the discharge gap D may be formed on the transparent electrode 55 by patterning. A material having a relatively high resistance and high visible light transmittance, such as ITO (Indium Tin Oxide), SnO2 (NESA), and the like, is used as a material of the transparent electrode 55. The transparent electrode 55 is formed by a thin film process such as deposition, CVD, and the like.
The bus electrode 59 is a belt-like metal electrode having a low line resistance, and is formed on the transparent electrode 55 so as to be thinner than the transparent electrode 55. A material having a relatively low resistance, such as Ag (silver), Al (aluminum), Cu (copper), or a laminated film of Cr (chrome) and Cu, is used as a material of the bus electrode 59. There are a wide variety of formation methods of the bus electrode 59. One example of the formation methods is a thick film process in which a thick film electrode is formed using a print calcination process by a thick film electrode material such as an Ag electrode paste that is mixed with an organic binder material. The formation methods also include a thin film forming process using a thin film electrode material including Al, Cu, and the like, and a thin film process in which a thin film electrode is formed by patterning using a photolithographic process.
The above-mentioned PDP tends to be higher in definition. For example, a full high-definition class (1920×1080) has been developed.    Patent Document 1: Japanese Published Patent Application No. 2003-123654